The International Atomic Energy Agency (IAEA)’s recent detection of uranium enriched to near weapons-grade levels in Iran should send a strong message to the United States and Europe that it is necessary to ratchet up diplomatic efforts to reduce the risk of a nuclear-armed Iran. While the spike in enrichment did lead the agency to begin negotiations on additional transparency measures with Iran, these steps alone are insufficient to mitigate the growing proliferation threat and stabilize the current crisis. It is imperative that the United States look to build on the positive momentum generated by the IAEA’s efforts to pursue additional steps to deescalate tensions.

From a technical perspective, Iran can now build a bomb more quickly than at any point in its history, if it made the decision to do so and undertook the necessary weaponization activity. This risk is amplified by domestic and geopolitical factors that might lead Tehran to conclude that the perceived security benefits of nuclear weapons outweigh the cost it will pay for developing them.

Since protests broke out in September, Iran has accused the West of supporting regime change objectives. Tehran may come to view nuclear weapons as necessary to deter foreign interference in its domestic politics and to preserve the current regime. Further acts of sabotage and the growing threat of military action against Iran’s nuclear program could also lead Tehran to determine that nuclear weapons are necessary to prevent future attacks.

While the combination of technical factors and political drivers increases the threat of proliferation, there is still time for diplomacy. Nothing in the IAEA’s Feb. 28 report suggests that Iran is accumulating uranium enriched to 84 percent, a level that can be used for nuclear weapons but is just shy of the 90 percent considered weapons grade–or that it is about to make a dash for the bomb. Central Intelligence Agency Director William Burns also said on Feb. 26 that there is no evidence that Iran has made a decision to pursue nuclear weapons. At the same time, Iran’s attempt to explain the presence of the 84 percent enriched particles as an “unintended” fluctuation in its 60 percent enrichment at Fordow strains credulity. But whether accidental or intentional, the enrichment to 84 percent highlights the challenge in discerning whether Tehran’s actions are intended to build leverage in future negotiations or to inch closer toward a nuclear-weapons threshold capability. Either way, Iran’s actions increase the risk of miscalculation and conflict.

While restoring the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action, would roll back Iran’s most proliferation sensitive activities, it is not a viable option at this time. The political space in the United States and the E3 (France, Germany, and the United Kingdom) for restoring the JCPOA has narrowed significantly since talks stalled in August over Iran’s extraneous demands. The United States and Europe are understandably focused on condemning Iran’s brutal crackdown on domestic protesters and countering Tehran’s support for Moscow’s war in Ukraine. But these policy goals and preventing Iran from obtaining nuclear weapons are not mutually exclusive. If Iran develops nuclear weapons, or is about to cross that threshold, it will be more difficult to counter Tehran’s destabilizing activities and domestic repression.

The Status Quo is Unsustainable

Since negotiations to restore the JCPOA stalled in August, the proliferation risk posed by Iran’s advancing nuclear program has grown significantly. Further escalation appears inevitable. The Raisi government has made clear it will continue to respond to perceived provocations by ratcheting up its nuclear activities. With several likely flashpoints in the coming months, the nuclear crisis will deepen and the risk of conflict increase.

The IAEA’s Board of Governors is under growing pressure to take further action against Iran for stonewalling agency inquiries into the country’s pre-2003 nuclear activities that should have been declared to the IAEA. The IAEA Board censured Iran twice in 2022 for failing to cooperate and each time Tehran retaliated, first by reducing monitoring of its nuclear activities and then by announcing it would ratchet up enrichment at the fortified Fordow site.

IAEA Director General Rafeal Mariano Grossi did announce that Iran and the IAEA discussed concrete measures to advance the investigation during his March 4 trip to Tehran. However, the spokesperson for the Atomic Energy Organization of Iran swiftly refuted Grossi’s characterization of the discussion, suggesting that, yet again, there is no agreed upon path to close the investigation and that it will remain an area of tension.

The Biden administration suggested in November that the Board will need to refer Iran to the Security Council, a logical next step, if Tehran fails to provide the IAEA with credible responses. While the IAEA Board is not required to take this step, failure to escalate after years of Iran stalling would undermine the agency and set a poor precedent for future cases of proliferation, even if Russia is likely to veto any new resolution targeting Iran.

Another flash point will likely come in October, when United Nations (U.N.) Security Council sanctions targeting Iran’s missile program are set to expire. Under Resolution 2231, Iran is prohibited from selling missiles and drones capable of delivering a nuclear weapon and certain technologies pertinent to building those systems without prior approval. The United States, the E3 (France, Germany, and the United Kingdom), and Ukraine have accused Iran of violating Resolution 2231 by selling drones to Russia, which Moscow is using against civilian targets in Ukraine. If Tehran continues to provide military support for Moscow and transfers additional drones, or possibly even ballistic missiles, it will be politically challenging for the United States and the E3 to allow the U.N. sanctions to expire, even though the measures have proven ineffective in halting Iran’s illicit weapons sales.

As permanent Security Council members and parties to the JCPOA, the United Kingdom or France could initiate “snapback” of U.N. sanctions without the full support of the permanent five members under an innovative mechanism in Resolution 2231 that ensures reimposition of sanctions cannot be vetoed. In response to such a move, Tehran may follow through on threats to withdraw from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which legally prohibits the country from developing nuclear weapons. It is imperative to deescalate the current crisis before Tehran acts on this threat and further accelerates its nuclear activities.

Even if Iran chooses not to escalate the crisis, the status quo is unsustainable. At present, the time it would take for Tehran to produce sufficient weapons-grade uranium for one nuclear bomb – the “breakout” time – is less than one week (it was 12 months when the JCPOA was fully implemented). While this short breakout time is concerning, one nuclear weapon does not provide Iran with a nuclear deterrent. If Iran’s program continues at its current pace, however, there is a risk that Tehran could stockpile sufficient amounts of highly-enriched uranium to build multiple nuclear weapons quickly. In a Feb. 28 IAEA report, the agency noted that Iran has 87 kilograms of uranium enriched to 60 percent and 435 kilograms enriched to 20 percent. That is likely enough for Iran to produce four nuclear weapons in less than a month. As that timeframe decreases, risk will increase.

Breakout time is also important because disrupting the acquisition of nuclear material is the best option for preventing a country from developing nuclear weapons. Enrichment occurs at known, declared facilities. It is more difficult to detect and disrupt the weaponization process, which could take as little as six months or more likely a year, because Tehran would divert the material to covert sites.

To date, the United States and Israel have been willing to tolerate the risk posed by Iran’s short breakout timeline. But if Iran begins enriching to weapons-grade levels or can rapidly produce enough material for multiple weapons, threat perceptions will shift. Israeli officials are already suggesting that military strikes may be “necessary” within the next year or two if Iran continues on its current nuclear trajectory (of course, the use of force absent an armed attack or imminent threat thereof would itself be unlawful, and would likely precipitate further conflict).

Toward A New Diplomatic Approach

Given the uncertain political commitment to the JCPOA in Washington and Tehran and urgency of the proliferation risk, the United States and its European partners need a new diplomatic strategy.

The most feasible option given political constraints in Washington would likely be a gesture-for-gesture approach that focuses on stabilizing the current crisis through unilateral measures that freeze or roll back the status quo. While similar measures could be negotiated in an interim deal, like the arrangement that stabilized Iran’s nuclear escalation in 2013 and created space for negotiations on the JCPOA, an interim deal may be more time consuming to negotiate and politically challenging in the current environment. To be sure, calibrating a gesture-for-gesture approach will not be easy and it is not a long-term solution to the Iranian nuclear crisis. It is designed to deescalate the current crisis and create the time and space for further negotiations. Those talks could be focused on restoring the JCPOA, but more likely a new paradigm will be necessary. So what types of gestures should each side pursue at the outset?

Restoration of the Additional Protocol

The Biden administration and remaining JCPOA participants should first encourage Iran to permit increased monitoring of its nuclear program. Additional verification measures would provide further assurance that Iran is not deviating from its declared nuclear activities—an objective made all the more necessary after Tehran was caught in January reconfiguring centrifuges at Fordow without notifying the IAEA—and deter diversion.

Currently, Iran is implementing its comprehensive safeguards agreement, as legally required by the NPT. Under that agreement, inspectors have access to facilities in Iran where nuclear materials are present. This agreement provides assurance that the IAEA will detect weapons-grade enrichment—eventually—but it is insufficient to ensure that Iran’s nuclear program is entirely peaceful and that there is no diversion.

Under a December 2020 law, Iran suspended implementation of its more intrusive safeguards agreement, known as the additional protocol, and a number of other JCPOA-specific measures, such as continuous surveillance at certain nuclear sites. As a result, IAEA inspectors have not been able to access certain locations that support Iran’s nuclear program but do not contain nuclear materials–such as centrifuge production facilities–since February 2021. The IAEA has raised concerns about the implications of this gap. It escalated its warning about the implications of this step in its Feb. 28 report, which said for the first time that the agency will be unable to reconstruct an accurate history of Iran’s nuclear activities. The report went on to warn that there will be a high degree of uncertainty in reestablishing baselines for certain materials such as centrifuge components and uranium ore concentrate. This has implications for diplomacy. It will be more challenging, for instance, for the IAEA to quickly and confidently verify Iran’s compliance with limits under either a restored JCPOA or a new deal.

Restoring the additional protocol would be the most straightforward option to give inspectors access to the sites and information necessary to provide assurance that Iran’s nuclear program is peaceful. The E3 urged Iran to take that step as a confidence building measure last year. However, the December 2020 law required Tehran to suspend that additional protocol and other JCPOA specific measures if the parties to the JCPOA failed to take steps on sanctions, including the normalization of bank relations and the sale of Iranian oil products. This suggests that the Raisi government may be unwilling or unable to resume any monitoring required by the JCPOA without the level of relief enumerated in the law. But the Biden administration is unlikely to remove the oil and banking sanctions, which are significant sources of U.S. leverage, following solely restoration of the additional protocol.

Other Monitoring and Verification Options

A more feasible option in a gesture-for-gesture approach would be to look at monitoring and verification options that exist outside of the JCPOA or were not included in the December 2020 law. JCPOA participants could also look to build on the recent transparency measures that Grossi announced after his March 3-4 trip to Tehran.

The March 4 statement from the IAEA and the AEOI said that Iran agreed to “further appropriate verification and monitoring activities.” Specifically, Grossi said Iran and the IAEA agreed to increasing the frequency of inspections at Fordow and reinstalling surveillance equipment that Iran disconnected, such as cameras and monitors that track enrichment in real-time (OLEMs). While Grossi said the details are still being negotiated, any increase in monitoring at this stage is useful. Reinstalling cameras at sites that the IAEA has not had access to since February 2021, for instance, would assist IAEA efforts to reconstruct a history of Iran’s nuclear program during the monitoring gap and to potentially deter diversion.

A new U.S. diplomatic strategy could seek first to build on this success to ensure optimal benefits. It is not clear, for instance, whether the IAEA will have regular access to the data collected by the surveillance cameras. Iran allowed cameras to operate from Feb. 2021 to June 2022, but the IAEA was not able to access that data and Iran said it would only hand it over if the JCPOA were restored.

It is also unclear whether an online enrichment monitor will be installed at Fordow, as there was not a machine there in the past. Reconnecting the OLEMs would help ensure timely detection of any enrichment beyond the declared levels. The challenges the IAEA is facing in obtaining an explanation for the 84 percent enriched particles underscores the benefits of the OLEMs.

If the negotiated modalities do not include regular access to surveillance data, access to the previous recordings, and an OLEM at Fordow, these proposals could be pursued in an initial round of gestures.

Additionally, a less politically sensitive alternative for increasing inspections would be for Iran and the IAEA to negotiate technical visits. Technical visits are voluntary arrangements whereby the state allows the IAEA access beyond what is permitted in a safeguard’s agreement. Technical visits to facilities that fall outside of the sites covered by the comprehensive safeguards could help provide assurance that Tehran is not diverting materials for a covert program and assist the agency in reestablishing a baseline in the future.

Increased transparency also benefits Tehran. Given the advanced state of Iran’s nuclear program and how quickly the country could breakout, the risk of Tehran miscalculating its space to maneuver and crossing a redline is increasing. Greater clarity about Iran’s actions and greater assurance that breakout will be detected rapidly reduces the risk that the United States, or more likely Israel, will resort to kinetic action to halt the country’s nuclear advances.

Capping Stockpiles in Gas Form

Beyond additional monitoring, which should be the primary priority, the United States should pursue additional gestures that maintain a longer breakout timeline for several nuclear weapons and freeze enrichment capacity at Fordow.

Given that Iran views its stockpiles of HEU as one of its most significant sources of leverage, it is unlikely to give the materials up in a “gesture-for-gesture” or interim deal. The Biden administration could propose limits on the size of the stockpiles kept in gas form (the form necessary for further enrichment) that reduces immediate proliferation risk by preventing Tehran from breaking out quickly to several nuclear weapons, while allowing Iran to retain its leverage. Tehran could blend down or convert to powder material produced at more than those levels.

Increased transparency would also provide greater assurance that any attempt to divert the material stored in gas form or enrich it further would be quickly detected, reducing the risk posed by limited gas stocks in the country.

Limits at Fordow

Limits on Iran’s deployment of IR-6 centrifuges at Fordow should also be considered. In November, Iran announced its intentions to install 14 cascades of IR-6 centrifuges and enrich uranium to 60 percent at that location. Currently, there are two cascades of IR-6 centrifuges and six cascades of the much less efficient IR-1 centrifuges installed at the facility.

While the IAEA confirmed that Iran is enriching to 60 percent at Fordow, it is not clear how quickly it will install the 14 cascades of IR-6 centrifuges. As of the Feb. 28 IAEA report, Tehran has not installed any additional IR-6s at the site.

Regardless of the pace of IR-6 installation, increasing the enrichment level and capacity at Fordow is significant because of the location of the facility. Fordow was built into the mountains near Qom, likely for the purpose of producing nuclear materials for weapons. It is a hardened facility that would be challenging to target with a military strike, particularly for Israel. For those reasons, Iran was prohibited from enriching uranium at the site for 15 years under the JCPOA. Limiting capacity at Fordow decreases the likelihood of Iran using it to breakout in a manner that would be more challenging to disrupt.

Limited Sanctions Relief

For their own part, the United States and its European allies should be willing to undertake limited sanctions relief commensurate with the technical steps Iran is willing to take. This could include limited oil sales and the unfreezing of Iranian assets held abroad. Allowing certain regional trade may be another route for providing Iran with limited relief. Where possible, Washington and its partners should support the provision of humanitarian aid, as well as economic policies that benefit and empower Iran’s middle- and working classes that have long borne the brunt of sanctions.

An Unpalatable Necessity

While the Biden administration continues to profess its support for a diplomatic solution to the Iranian nuclear crisis, it will face severe criticism for engaging with the Raisi government, or for implementing any unilateral gestures that provide Iran with monetary benefits. Critics of diplomacy that are pushing for the United States to refrain from negotiations with Iran, or gestures that could stabilize the current crisis, argue that such actions legitimize the current regime. But as unpalatable as these steps may be, the alternatives – possible military action or the prospect of a nuclear-armed Iran – are worse.

The status quo, whereby Iran advances its nuclear program and the United States increases sanctions, is unsustainable. The risk will likely rise to the point where the United States, or more likely Israel, decides to take military action to reduce the threat. Israeli officials have publicly suggested that a strike will be necessary within the next two years. Prime Minister Benjamin Netanyahu said on Feb. 21 that the only thing that has stopped “rogue nations from developing nuclear weapons is a credible military threat or a credible military action.”

The Biden administration has made clear it will use military force to prevent a nuclear-armed Iran if necessary, but proponents of this strategy should also be clear about the likely consequences of that route. Military strikes or sabotage could reduce proliferation risks in the short- to medium-term, but Iran previously has responded to sabotage attempts by further ratcheting up its nuclear activities. A military strike against key facilities may also lead Tehran to assess that nuclear weapons are necessary to preserve its own sovereignty and territorial integrity. Strikes could also escalate into a broader conflict, with a devastating impact on the Iranian people, regional countries, and the many U.S. troops in striking range.

Given the gravity of these consequences, the United States and its European partners must pursue every diplomatic avenue to deescalate the nuclear crisis. The IAEA’s recent success in negotiating additional transparency measures provides an important window of opportunity to capitalize on the current momentum and pursue further steps that reduce risks. It is past time the urgency of diplomacy matched the urgency of the proliferation risk – and the risk of disastrous military conflict if that risk is ignored.

Image: Iranian Foreign Minister Hossein Amir-Abdollahian (2nd L) meets with International Atomic Energy Agency (IAEA) chief Rafael Grossi (2nd R) in Tehran on March 4, 2023 (Photo by ATTA KENARE/AFP via Getty Images).